Prior art stop apparatuses for use with collets and spindles are shown in U.S. Pat. Nos. 1,014,051; 2,398,278; 2,423,551; 2,922,656; 3,115,798; 3,188,101; 3,311,383; 3,360,276; 3,385,607; 3,615,101; 3,876,214; and 4,702,484.
A prior art stop for collets, manufactured by the Hardinge Company, and which is in wide use, is shown in FIG. 1 of the attached drawings.
Some prior stop apparatuses are configured to fit into collets or spindles that have specific configurations and dimensions. Other devices, such as shown in U.S. Pat. Nos. 2,398,278 and 3,615,101, fit within the bore of a lathe spindle or collet and are expandable against the spindle or collet to hold the stop in position. Requiring each stop apparatus to be adaptable to a particular size and configuration of collet (or spindle) presents an economic burden in that a wide variety of stop apparatuses would be needed by a machinist to fit each collet of a range of collet sizes. For example, with the Hardinge device, the part termed the stop holder is dimensioned to fit a specific size of collet.
The collet stop shown in U.S. Pat. No. 3,615,101 is retained in place within the collet by a member that is expanded by tightening a nut having a conical face against a conically shaped end of the expandable member. The collet stop is difficult to use because the nut for expanding the expandable member is located inside the collet and thus is difficult to reach.